Numerous studies have demostrated that patients with affective disorders have cholinergic supersensitivity. The neuroendocrine challenge test to measure it employs pyridostigmine, which increase cholinergic tone in the hypothalamus, thereby releasing GH. This is a single study indicating that the patients who were probably bipolar and had brief improvement in their thought disorders after a trial with physostigmine, went on to be lithium responders. We wish to test the hypothesis that patients with affective disorders have cholinergic supersensitivity and determine if this supposed supersensitivity is a marker of response as well as certain personality traits, psychosensory experience, and the results of the challenge test. To date 10 patients have been enrolled (3 controls and bipolar). The investigators would like to make changes to this study. In order to allow for a greater variety of patients to enter the protocol. The investigators are proposing an amendment to the protocol that they hope will allow for improved recruitment of subjects. Although the investigators wish to change the protocol by broadening the inclusion criteria, the actual challenge test itself will be performed as per the original protocol.